Development of Stable, High Power, High Pressure Arc Air Heaters for a Hypersonic Wind Tunnel

Eschenbach, R.C.; Skinner, G. M.

doi:10.21236/ad0266907

Cited by 9 publications

(2 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…[High enthalpy plasma generator with magnetic field stabilization (P = 4.8 MW) (SNIAS [130]). ] [131] est présenté sur la figure 52 avec une tuyère supersonique. Les caractéristiques de ce type de générateurs sont résumées sur la figure 53.…”

Section: Générateurs Stabilisés Par Champ Magné-unclassified

Les générateurs à plasma

Kassabji

Fauchais

1981

Rev. Phys. Appl. (Paris)

View full text Add to dashboard Cite

Cet article présente dans une première partie une étude des phénomènes rencontrés dans les générateurs à plasma. Après une définition sommaire du plasma et de sa génération, nous exposerons les caractéristiques essentielles des arcs plasmas et leurs particularités dans la distribution du potentiel. Le rôle des électrodes apparaît dans les phénomènes d'attachement ainsi que dans les jets cathodique et anodique créés. Les différentes méthodes de stabilisation de ces arcs (par la paroi, par transpiration, par injection tourbillonnaire d'un liquide ou d'un gaz ou par champ magnétique) sont exposées ainsi que le comportement de l'arc dans son circuit électrique d'alimentation. Les phénomènes propres aux électrodes dans les générateurs à plasma à courant alternatif sont brièvement indiqués et enfin l'usure des électrodes est discutée permettant ainsi d'évaluer la durée de vie des électrodes sous différentes atmosphères. La seconde partie est consacrée aux principes de conception et de modélisation des générateurs à plasma et la forte influence des propriétés de gaz à haute température. Des relations semi-empiriques permettant la modélisation des différents réacteurs à plasma sont déterminées pour divers gaz. Dans la troisième partie, et après l'étude des caractéristiques principales des générateurs à plasma à faible enthalpie et de leurs utilisations, nous présentons les divers générateurs à plasma utilisés. La classification faite est liée d'une part à un paramètre de structure : nature des électrodes (chaudes ou froides) et d'autre part à deux paramètres de fonctionnement : mode de stabilisation de la colonne de l'arc et nature des gaz plasmagènes utilisés (oxydants, neutres ou réducteurs). Enfin, la dernière partie traite des générateurs à plasma à forte enthalpie classés selon les modes de stabilisation utilisés

show abstract

Section: Générateurs Stabilisés Par Champ Magné-unclassified

Les générateurs à plasma

Kassabji

Fauchais

1981

Rev. Phys. Appl. (Paris)

View full text Add to dashboard Cite

show abstract

“…This heater was of the constricted type with rotating arc column and swirl air-injection as conceived by Eschenbach. 20 The heater was either connected directly to the nozzle system or coupled to the nozzle through a settling chamber. The test section consisted of a 6-ft-diam-cylindrical enclosure housing the nozzle exit, flow survey struts, actuators, measuring probes, and entrance cone to a 10-in.…”

Section: Description Of Experimental Apparatusmentioning

confidence: 99%

Nonequilibrium regime of airflows in contoured nozzles - Theory and experiments.

Zonars

1967

AIAA Journal

View full text Add to dashboard Cite

Experimental data are compared with theory for the expansion of high-temperature air through a 9.492-in. exit diameter, contoured nozzle. An exact numerical calculation of a one-dimensional equilibrium and nonequilibrium expansion based on the measured potential nozzle flow is included. Thermodynamic calculations are based on rotational, vibrational, and electronic partition functions with associated corrections for anharmonicity, rotational-vibrational coupling, and rotational stretching. Flow properties are calculated for an air model containing N£, C>2, NO, N, O, and argon. An experimental program utilizing a 3-Mw, d.c. arc heater provided design reservoir conditions of 114.7 atm and 4120°K to produce a Mach number 10.23 "near-equilibrium" flow. Fully instrumented nozzle exit surveys of mass flux, impact pressure, and steady-state calorimetry along with nozzle wall pressures were utilized to derive freestream velocity, density, and total enthalpy. A second case with reservoir conditions of 132.7 atm and 5725°K was found to be in good agreement with the nonequilibrium expansion process. A third case, reservoir conditions of 35.4 atm and 5361 °K, yielded a nonequilibrium, parallel flow resembling a gas nearly "frozen" directly after the nozzle throat. Nomenclature A= one-dimensional nozzle area, cm 2 or ft 2 AI = coeff in equilibrium const, Table 3 B = exp of T in equilibrium const, Table 3 CMJ = concentration of specie j, mole/cm 3 d* = nozzle throat diam, in. E 0i = zero point energy per mole of specie i, dyne cm/mole Ej)i = heat of reaction per mole of specie i, dyne cm/mole, or cal/mole HT = total enthalpy per unit mass of fluid, dyne cm/g or Btu/lbm Hi = enthalpy per mole of specie i, dyne cm/mole h = static enthalpy per unit mass of fluid, dyne cm/g or Btu/lbm K pr = equilibrium const for reaction r, Table 3 kb r -backward rate constant for reaction r, (cm s ) 2 /mole 2 -sec kf r = forward rate constant for reaction r, cm 3 /mole-sec, Table 1 M = Mach number MJ = molecular weight of species j, g/mole n = number of compounds m = mole number of species i, mole/g of mixture m° = mole number of reference species i, mole/g P T = reservoir pressure, atm p = local pressure, atm or dynes/cm 2

show abstract

Developments in Inorganic Arc Plasma Chemistry

Landt¹

1970

Angew. Chem. Int. Ed. Engl.

View full text Add to dashboard Cite

indicate a strong preference for the formation of hydrogen fluoride with) = 2. Accordingly transitions from v --2 to v = 1 also occur preferentially in lasers pumped by reaction (1). This emission appears in the infrared region between 2.7 and 2.9pm. In laser systems in which the additional reaction (6) contributes to the pumping, higher vibrational states up to v = 6 are excited. The emission at about 3 pm corresponds to a large number of vibrational-rotational lines, but n o detailed rate constants have been published so far 15,141. This description of the parameters of chemical laser emission has been confined to hydrogen fluoride lasers as the area that has been most extensively studied. In view of the intense activity in this field, however, similar results may be expected in the near future for other, new chemical lasers. Possible ApplicationsThere is considerable scope for the use of these lasers in various fields. In chemistry, sources of strong monochromatic infrared radiation offer the longterm prospect of use as a "selective Bunsen burner" with the object of carrying out chemical reactions with a controlled supply of energy in certain vibra- (preparation e.g. of compounds containing nitrogen, C-N and C-F compounds, ozone, nitrides, cyanides, carbides, metal oxides, and metals from metal oxides and from halides). Development and Present Position of Plasma ChemistryA plasma is nowadays generally taken to be a partly or completely ionized gas that is externally electrically neutral, conducts electricity, and has a higher internal energy than an un-ionized gas. The energy required for the production and maintenance of a plasma can [*I Dr. U. Landt Knapsack AG 5033 Knapsack bei Koln (Germany) be supplied as heat or as electrical or mechanical energy. The most important methods for the supply of electrical energy are arc and glow discharges and electrodeless discharges (high frequency and microwave discharges). Only the arc plasma and its use will be discussed here.The term "plasma chemistry" is at present used only reluctantly in the literature. Since chemical bonds d o not exist at the high temperatures characteristic of most types of plasma, the term is really self-contradictory. Nevertheless, it is shorter than any of the 780 Angew. Chem. internat. Edit. 1 Vol. 9 (1970) 1 No. 10 alternatives, and will therefore be used here in the sense of the performance of chemical reactions in o r with the aid of plasmas.Chemical plasma processes have been known since the industrial production of oxides of nitrogen by "combustion of air" in the flame arc furnace (Birkeland and Eyde; Schonherr and Pauling). The development of plasma chemistry stopped for a long time after the replacement of this process by the cheaper combustion of ammonia. This standstill was mainly due to the high cost of electricity and technical problems.For some 10 to 7 5 years, however, plasma chemistry has been developing rapidly, at least on the research side. The intense activity in high-temperature physics in connection with nuclear fu...

show abstract

Development of Stable, High Power, High Pressure Arc Air Heaters for a Hypersonic Wind Tunnel

Cited by 9 publications

References 0 publications

Les générateurs à plasma

Les générateurs à plasma

Nonequilibrium regime of airflows in contoured nozzles - Theory and experiments.

Developments in Inorganic Arc Plasma Chemistry

Contact Info

Product

Resources

About